1. Field of the Invention
The invention relates in general to a transmission cable intended for the transmission and distribution of electrical power, and typically, high voltage electrical power. More particularly, the transmission cable of the present invention separates the mechanical strength member from the electrical current carrying member, such that each can be designed and configured without dependence on the other.
2. Background Art
The demand for transmission and distribution cables increases with the greater demand for electricity. As the appetite for power increases, new electrical cables continue to be installed. Additionally, to increase capacity, other electrical installations are rewired with cables of greater capacity.
Traditionally, such electrical cables comprise a central stranded steel core which is wrapped in a stranded aluminum conductor. Such cables have been utilized for decades with very little change. Amongst other drawbacks, such cables are susceptible to excessive sag in certain climates and under certain operating conditions. Furthermore, such cables are susceptible to corrosion in other environments.
To combat the shortcomings, other composite based solutions have been developed. Certain such solutions are described in U.S. Pat. No. 7,060,326; U.S. Pub. Nos. 2004-0131834; 2004-0131851; 2005-0227067; 2005-0129942; 2005-0186410; 2006-0051580; U.S. Prov. Pat. App. No. 60/374,879; and PCT Pub. No. WO 03/091008, the entire disclosures of each of the foregoing are incorporated herein by reference in their entirety. Such solutions have replaced the central steel stranded core with a composite material having a core component formed from a carbon fiber material embedded within a matrix and an outer component formed from a fiber material other than carbon embedded within a resin. The core is formed by pultruding the various fibers through pultrusion dies.
Despite these additional developments, the continuing drawback associated with the foregoing conductor solutions is that the mechanical strength member is intertwined and inseparably coupled with the current carrying conductor. As such, the current carrying conductor is limited in construction due to the considerations of its mechanical strength. Additionally, the mechanical strength member is limited by its compatibility with the conductor. For example, due to the relationship between the conductor and the core, the heat requirements of the core are quite elevated, due to the proximity thereof with the conductor. Additionally, as the conductor and the core are both spliced and dead ended together, it is necessary to consider both the conductor and the core when configuring such a splice or a dead end. Such considerations often lead to a compromised solution.
It is another object of the present invention to separate the mechanical strength member from the current carrying conductor in transmission lines.
It is another object of the invention to provide independently designed and configured mechanical strength members and current carrying conductors in transmission lines.
These objects as well as other objects of the present invention will become apparent in light of the present specification, claims, and drawings.